1. Field of the Invention
The present invention relates to a shift control device for continuously variable transmission for a vehicle, and a vehicle incorporating same. More particularly, the present invention relates to a shift control device which inhibits shifting of gear ratio of continuously variable transmission during a rolling behavior of a vehicle, such as a motorcycle.
2. Description of the Background Art
There are several known shift control devices which inhibit shifting of a gear ratio of an automatic transmission by detecting a steering angle and a speed of a vehicle. An example of such shift control device is disclosed in Japanese published patent document JP-A-2004-116752.
According to the Japanese published patent document JP-A-2004-116752, as shown in FIGS. 1 and 5 (not included in this disclosure) thereof, a hydrostatic continuously variable transmission 5 includes a drive shaft 8, a fixed capacitance hydraulic pump 6 and a variable capacitance hydraulic motor 7 integrally mounted on the drive shaft 8, and a hydraulic closed circuit formed between the fixed capacitance hydraulic pump 6 and the variable capacitance hydraulic motor 7.
When a driven gear 4 which is meshed with a drive gear 3 mounted on a crankshaft 2 of an internal combustion engine 1 is rotated, the fixed capacitance hydraulic pump 6 is also rotated. This rotational force is outputted to the drive shaft 8. Here, in response to a change of an inclination angle of a movable oblique plate incorporated in the variable capacitance hydraulic motor 7 by an inclination angle control mechanism 10, a shift ratio of the hydrostatic continuously variable transmission 5 is changed.
To be more specific, the above-mentioned inclination angle control of the movable oblique plate is performed by controlling driving of a control motor 11 using an ECU 30.
A vehicle speed signal from a vehicle speed sensor 33 and a steering angle signal from a steering angle sensor 38 mounted on a handlebar are inputted to the ECU 30, which allows the inclination angle control mechanism 10 to change the inclination angle of the movable oblique plate in response to these signals.
When the inputted vehicle speed and steering angle are calculated and a calculation result satisfies predetermined conditions, shifting (shift down) by the hydrostatic continuously variable transmission 5 is inhibited. However, for example, when the rolling behavior during slalom traveling (e.g., zigzag traveling between obstacles) of a vehicle or the like is fast, it is desirable to inhibit the shifting of gear ratio even when the calculation result of the vehicle speed and the steering angle does not satisfy the predetermined conditions.
Accordingly, it is an object of the present invention to provide a shift control device of a vehicle which can restrict shifting of gear ratio during the rolling behavior of a vehicle body i.e., during slalom traveling (including fast traveling) and quickly turning of handlebar of the vehicle.